Electrical heating apparatus.



No. 761,205. PATENTED MAY 3l, 1904. C. E. CARPENTER. ELECTRICAL HEATINGAPPARATUS.

APPLICATION FILED JAN. 27. 1904. N0 MODEL` 2 SHEETS-SHEET I.

LA f @A No. 761,205. PATENTED MAY` 31, 1904.

l G. E. G PBNTER.

ELECTRICAL v ING APPARATUS.

APPLIOAT D JAN. 27. 1904.

N0 MODEL. 2 SHEETS-SHEET 2.

ff le Patented May 31, 1904;

UNITED STATES PATENT OFFICE.

I CHARLES E. CARPENTER, OF NEVITV YORK, N. Y., ASSIGNOR TO CUTLER HAMMER`MANUFACTURING COMPANY, A CORPORATION OF WIS- CONSIN.

ELECTRICAL HEATING APPARATUS.

SPECIFICATION forming part of Letters Patent No. 761,205, dated May 31,1904.

Application filed. January 27, 1904. Serial No. 190,786. (No model.)

T0 all whom it may concern:

Be it known that I, CHAnLns E. CARPENTER, a citizen of the UnitedStates, and a resident of New York city, in the county of New York andState of New York, have invented certain new and useful Improvements inElectrical Heating Apparatus, of which the following is a specification,reference being had to the accompanying drawings, which form a parthereof.

My invention relates to certain new and useful improvements in thatclass of apparatus in which the resistance or conductor is heated by thepassage of an electric current and in which the heat is transmittedlargely by conduction to an outer or surrounding shell, plate,or body,which is in close mechanical relation to, but electrically insulatedfrom, the resistance or conductor by suitable ireproof insulatingmaterial.

The object of my invention is to improve the construction of theapparatus generally, to make it simpler and more economical, to providea very intimate mechanical contact between the conductor and theinsulating material and between the insulating material and the platesor exterior shell of the apparatus, while at the same time thoroughlyinsulating the conductor from the plates, to hold the conductor and theinsulating material rmly in place and to prevent their being broken orcracked or distorted, and to simplify the method y'of manufacture.

Another object of my invention is to incase or perfectly seal theresistance or conductor in a fireproof vitreous material and also toplace the same with reference to the plate or plates to be heated, so asto provide for the rapid conduction of heat through the insulation tothe said plate or plates.

Another object is to protect the conductor or resistance mechanically,so that excessive iow of current through the same, such as would beproduced by the overloads incurred incommercial service, shall notdislodge, fuse, or distort the resistance or conductor. v

My invention alsoconsists in the combination, in an electrical heatingapparatus, of the plates to be heated in the completed article, avitreous insulating material between the said plates pressed betweenthem when heated, so as to conform accurately to the shape of the platesand to be in intimate mechanical contact therewith, and an electricalresistance sealed within the insulating material.

My invention also consists in making thel insulating material of a thinlayer of vitreous materialand in making it incase and protect theresistance, while at the same time insulating it from the plates, theinsulating material being pressed between the plates while in a moltenor hot state, so that it entirely fills the space between said plates,and being lcooled in said position in contact with said plates.

My invention also consists in so shaping the plates as to make themadapted to form a mold in which 0r between the parts of which theinsulating material is pressed into shape, the insulating material beingcooled in said mold under pressure and having as a result of this anintimate mechanical contact with the conductor or resistance as well aswith the plates and being held firmly in place lagainst distortion orbreakage.

My invention also consists in certain other features and combinations ofparts hereinafter described and claimed.

My improved method is illustrated and my improved apparatus shown in theaccompanying drawings, in which- Figures 1 to I illustrateone form of myimproved method of making such apparatus, Figli showing the completedapparatus thus produced. Figs' to 8 show a modification of my improvedmethod and apparatus. Figs. 9 and 10 show further modifications.

Referring to Figs. l to 4, l is a metal support or plate, preferably asheet of cast-iron. Atop or plan view of this plate is shown in Fig. l,and Figs. 2, 3, and 4 show sectional views of the same` on the line X Xof Fig. 1. The plate l is provided with a recess, as shown, adapted toreceive a sheet of ordinary windowglass 2. This sheet of ordinarywindow-glass is placed in the recess of plate l, and then a resistancewire or conductor 3, preferably of the refieXed type, is laid over thesurface of the sheet of glass 2, as illustrated in Fig'. l. A secondsheet or layer of glass 4L is then placed on top of the conductor 3, asillustrated in Fig. 3, and then another metal plate Y5 isl placed on topof the sheet of glass 4, as shown in said figure. 6 represents screws orother fastening devices placed at the corners or in any suitableposition and are adapted to screw into threaded holes 7 in the lowerplate l. By means of these screws the upper and lower plates arefastened or bound together, and thus the parts of the device are heldfirmly in place. The apparatus is then substantially in the conditionshown in Fig. 3. In this condition the parts are then submitted to ahigh temperature sufiicient to bring the glass to a molten or softcondition, and when in this condition the plates l and 5 are forcedtogether` by any suitable means, thus pressing the sheets of g'lassaround the conductor 3 and causing the two layers of glass to unite andincase the interposed conductor. The glass fills up the space betweenthe plates and between the different parts of the conductor and forms athin homogeneous compact and solid layer of insulating' material,holding' the conductor in place while 'insulating it from both platesand at the same time making intimate mechanical contact with both theconductor and themetal plates. The device is then cooled in thiscondition, and while being cooled the screws or other fastening's aretightened, so as to hold the parts firmly together and maintain theintimate contact. The apparatus is then as shown in Fig. L

Amodification of my invention is illustrated in Figs. 5 to 8, in whichFig. 5 is a top or plan l view of the device with the upper metal plateand the upper glass plate removed, and Figs. G, 7, and 8 arecross-sections on the line e fr of Fig. 5. In the method which isillustrated in these figures al third or interior sheet of glass 8 isemployed, as clearly shown in Fig. 6, around which the resistance 3 iswound. The lower plate 1 is made in the same form as already explained,and a sheet of ordinary window-glass 2 is placed in the recess in saidplate. The resistance-wire 3 is wound around the glass plate 8 and isthen placed in position, as shown in Fig'. 6. Then the upper sheet ofglass is laid on top of the resistance and the upper metal plate placedon top of this and the parts secured together by means of fastenings, asrepresented in Fig. 7. The apparatus in this condition is then submittedto a temperature suflicient to soften the sheets of glass, and the metalplates are pressed together while the glass is in this condition, as aresult of' which the glass is compressed around the resistance so as tofill up completely the space between the metal plates and so as to forman apparatus such as is illustrated in Fig. 8.

In Fig. 9 I have illustrated another modification of my invention inwhich a sheet of' mica 9 or similar material is interposed between thevitreous insulating material and cach of the metal plates. This docs notmaterially affect the intimate mechanical contact between the insulatingmaterial and the plates, and if in any waythe resistance-wire 3 shouldbe displaced at any point in the insulating material, so as to lie closeto the metal plate, the sheet of mica would still serve to insulate theresistance from that plate. In other words, the mica sheet would serveto prevent the groundingl of the resistance-wire. In other respects themodification illustrated in Fig'. 9 is exactly like that shown in Fig.8.

In Fig. l0 I have shown another form of' apparatus made in substantiallythe same way. In this case the lower metal plate l is made very thickand is provided with a deep recess into which the upper plate 5 isadapted to lit. This form of apparatus is very useful in an electricsad-iron, the flange of the plate l operating to prevent the influx ofwater into the resistance and insulation when, as often happens in theuse of such sad-irons, they are dipped in water by operators to reducetheir temperature.

The inleading wires for making internal connections to the resistancemay consist of any suitable metal of larger cross-section or betterelectrical conductivity than the resistance-conductor and may be brazedor firmly clamped in any suitable way to the same. These terminals,which are marked l0 in the drawings, may be of any convenient number,depending upon the character and the purpose of the apparatus. In Fig. la pair of' terminals lO l() are shown coming out from the oppositecorners of the plate; but terminals may also be placed at interveningpoints, such as l1 l1.

In Fig. 5 the intervening glass plate 8 is represented as being made intwo parts, around which the resistance is separately wound, the twoparts of the resistance being connected at l2. A terminal may beinserted at 12, if desired, as represented in this Fig. 5.

Heretofore in some types of heaters it has been deemed essential thatthe insulation should adhere to or become apart of the plate tobeheatedas, for example, where porcelain enamel or glaze has been used.In my invention it is not essential that the glass adhere to the metal;but, on the contrary, it is better that it should not so adhere, and toaccomplish this result I treat the surface of the iron or metal plates land 5 before heating with a thin coat of graphite or powdered soapstoneor powdered mica or similar material to prevent the adhesion of theglass to the metal during the process of manufacture, or, as alreadyexplained, I insert between the insulating' material and the plates asheet of mica or similar material as illustrated in Fig. 9.

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aereos Asa result of this the apparatus can be more readily repaired oraltered if it becomes necessary to insert another resistance while usingthe same plates, for the parts can be readily unscrewed or disconnected,and as the glass or insulating material does not adhere to the metalplates they can be taken apart and a new resistance and insulationsubstituted in the manner already explained.

The outer shell or casing or plate may con sist of one or more pieces,which may vary in thickness and shape as best suited to therequirements. For example, in an atmosphere-heating apparatus thesurface of the plates may be extended in corrugations for increasing thesurface for dissipating heat, or in an electric sad-iron one of theplates may be comparatively thick, so as to form the ironing surface orbottom of the iron, while the other plate would form the top of theiron. By forming recesses in the plates, and thereby providing flangesalong their edges, I prevent the' overflow of 'the molten glass while itis under pressure and at a high temperature during the process ofmanufacture. In this way I also prevent the running or spreading of theglass when it is hot, which might destroy the resistance or cause itsdisplacement and which might also thin out the insulation, especially atthe edges. In this way also the glass is prevented from falling outaround the edges of the apparatus in case of a fracture of the glass atthese points due to heavy overload in service or to rough usage or anyother such cause.

It will be seen that in the apparatus so constructed the resistance-wireis not only completely sealed from the atmosphere, but a thin wall ofhighly-electrical insulating material results, while at the same timethe glass being pressed against the surface of the plates while moltenmakes intimate mechanical contact therewith, allowing of a readyconduction of heat. Such an apparatus is very strong and very durable.It has been' known to run in actual use for days at a temperature of atleast 1,300O Fahrenheit without alteration of resistance or showing anyweakness.

It is evident that two or more resistances with or without interveninglayers of metal may be embraced between the outside casing or plates,according to requirements. It is also evident that instead of. metalother material may be employed in certain cases to form the outsideshell or plates. Also flat metal ribbon or even carbon may be employedas a resistance instead of wire.

l/Vhat I claim as new, and desire to secure by Letters Patent, isi l. Inan electrical resistance or heating apparatus, the combination of platesto be heated, a vitreous insulating material between said plates pressedbetween said plates when hot so as to conform to the shape of the platesand to I be in intimate contact therewith, and an electrical resistancesealed by the surrounding insulating material, substantially asdescribed.

2. In an electrical resistance or heating apparatus, the combination ofplates to be heated, an electrical resistance between said plates, athin layer of vitreous insulating material ineasing and protecting theresistance and insulating it from the plates, the layer of insulatingmaterial being pressed between said plates when hot so as to entirelyfill the space between said plates and being cooled in said position,

whereby there is close mechanical contact between the resistance, andthe insulating material and between the insulating material and theplates, substantially as described.

3. In an electrical resistance or heating apparatus the combination ofplates adapted to y form a mold in which the insulating material ispressed into shape, and thereafter to be used as the heat-conductingplates of the completed apparatus, an electrical resist-ance betweensaid plates, a thin layer of vitreous insulating material incasing andprotecting the resistance andinsulating it fromthe plates, the layer ofinsulating material being compressed between sid plates, and having anintimate contact with the resistance and the plates formed by beingheated and cooled under pressure Ain contact therewith, substantially asdescribed.

Ll. In an electrical resistance or heating apparatus, the combination ofplates adapted to form a mold in which the insulating material ispressed into shape, and thereafter to be used as the heatingconducting-plates of the completed apparatus, an electrical resistancebetween said plates, a thin layer of vitreous insulating materialincasing and protecting the resistance and insulating it from theplates,

the layer of insulating material being compressed between said plates,and having an intimate contact with the resistance and the plates formedby being heated and cooled under pressure in contact therewith, andfastening devices to hold the parts firmly together, substantially asdescribed.

5. In an electrical resistance or heating apparatus, the combination ofplates to be heated, a vitreous insulating material between said plates,sheets of mica or-similar material between the insulating material andthe plates, the insulating material being pressed between said plateswhen hot so as to conform to the shape of the plates and so as to causethe parts to be in intimate contact, and an electrical resistance sealedby the surrounding in sulating material, substantially as described.

6. In an electrical resistance or heating apparatus, the combination ofplates adapted to form a mold in which the insulating material ispressed into shape, and thereafter to be used as the heat-conductingplates of the completed apparatus, an electrical resistance between saidplates, a thin layer of vitreous insiO IIO

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sulating material incasing' and protecting the resistance and insulatingit from the plates, a sheet of mica or similar material between theinsulatingmaterial and each plate, the insulating' material beingcompressed between said plates and having` an intimate Contact with theresistance and with the plates or the mica sheets, said intimate Contactbeing` caused by the heating and Cooling of the insulating ma- IO terialunder pressure while in Contact with said parts, and 'fastening devicesto hold the parts firmly together, substantially as' described.

In testimony whereof l have signed my name to this speeilieation in thepresence of two subscribing' witnesses.

CHARLES E. CARPENTER.

Witnesses:

EDWIN Suelen, F. F. CRAMPTON.

